public class StrBuilder {
    //  打1个注释
//  再测试一下 git
    public static void main(String[] args) {
        StringBuilder builder=new StringBuilder();
        String a="Hello",b="World";
        builder.append(a);
        builder.append(" ");
        builder.append(b);
        String completedString = builder.toString();
        System.out.println(completedString);
    }
}
